Chang-Hyung Lee, M.D., Ph.D.

Anatomy of Ankle & Foot

Ankle

Introduction

Most frequently injured major joint

3 main articulation: distal tibiofibular j (syndesmotic)

ankle j (talocrural)

subtalar j (talocalcaneal)

Coronal View of ankle js.

1. Distal Tibiofibular joint

Tibiofibular syndesmosis

Upward 3~5 mm prolongation of the synovium of the ankle j

Distal focal thickening of the inteross. Memb

Interosseous lig.

Ant.& pot. Tibiofibular lig., transverse lig.

2. Ankle Joint Articular surface of the talar dome, distal ends of the tibia &

fibula , covered with cartilage

Hinge type: dorsiflexion : ~ 30◦ DF, ~50 ◦ PF

In extreme PF: some lateral motion is allowed

(Ankle mortis - post. Half talar dome is narrower than ant.

Half )

Supporting structures: fibrous capsule, MCL, LCL

Capsule: medial & lateral malleoli, acetabular margin of the

tibia, talus

2. Ankle joint: LCL complex

Lateral Ligament Complex

Ant. Tibio-fibular l.

ATFL

CFL

Pos. Talofib.L

Transverse Tibiofibular

Pos. tibiofibul. L

ATFL : least strong, m/c injured prevents ant.talar motion

CF : longest prevents excessive inversion

PTF: strongest,deepest prevents post. Talar shift

2. Ankle Joint : MCL complex

2. Ankle Joint : MCL complex

Tibiotalar

Tibiocalcaneal

Tibionavicular

Superf. & deep l.

Deltoid: stronger, extensive

Ant : to navicular Post to talus

Interm : to sustentaculum tali

2. Ankle joint

Ankle stabilizer

Coronal view: CFL, deltoid

In ankle PF: A T F L (vertical), resist varus deformity

In ankle DF: TFL is stressed

3. Subtalar joint

1. Post. Talocalcaneal j.: post. Subtalar j.

: supported by a fibrous capsule, ant,lat, post. Talocalcaneal lig.

10~20% : communicate with the ankle j.

Inversion & eversion movement

2. Talocalcaneonavicular j.: ant. Subtalar j.

: reinforced by dorsal talonavicular lig.

Spring (plantar calcaneonavicular) lig.

: ant. Of sustentaculum tali~undersurface of the navicular

Major supporter of longitudinal arch

4. Anterior Tendons

Dorsiflexed

Dorsiflexed + Inversed

4. Anterior tendons

1. TA

: most medial side ~ medial surface of medial cuneiform,

plantar aspect of the base of the 1st metatarsal

DF, inversion of ankle

2. EHL

3. E D L : divides into 2~5th toes

4. P Tertius : aids in DF, eversion

• Superior & inferior extensor retinacula

: prevent tendon bowstring action

5. Lateral tendons

1. Peroneus longus

2. Peroneus brevis : smaller, lies anterior

(3) peroneus quartus: accessory m. from PB

Retinacular : superior & inferior

Peroneal tendons turn forward below the lateral malleolus

and rest on the lateral aspect of the calcaneus

6. Medial tendons

Ant~ post. Flexor tendons : TP, FDL, FHL

1. T. P.

: inverter, major stabilizer of the hindfoot

oval shape, twice larger than FDL..

below med. Malleolus , superficial to the spring lig.

to 3 cuneiform & base of the 1~4 metatarsals

if, ruptured acquired flat foot

2. FDL

3. FHL : most lateral, runs inferomedially of the tibia

inferior aspect of the sustentaculum tali.

6. Medial tendons

Flexor Retinaculum Tibial n.

6. Medial tendons

Tibialis Posterior

Medial Malleolus

Tibialis Anterior Flexor H. L

Achilles

7. Posterior tendons

1. Achilles tendons (tendo calcaneus)

: longest, thickest, strongest tendon in the body (12~15 cm)

Descends vertically in the midline to post. Of calcaneus

Cross section: flattened

crescent shape ( flat or concave in anterior margin &

convex posterior margin)

- at distal insertion: entirely convex

Fibers of tendon twist laterally (90°)

Karger triangle : separated from FHL by fat pad, just

proximal to its insertion

7. Posterior tendons

Not invested by a tendon sheath

Enveloped by a paratendon : dorsal, lateral, medially

2~6 cm cranial to its insertion : hypovascular area

: tendon rupture occurs

• Insertion

: enthesis made of a intervening layer of fibrocartilage,

intermeshing into the bone marrow of the calcaneus

(strong, less tendon rupture)

2. Plantaris : medial border of the Achilles

small, long tendon

7. Posterior tendons

Achilles

Plantaris

Kager fat pad

8. Neurovascular structures

Ant. : Deep peroneal n. , ant. Tibial a.

1. Deep peroneal. N

- Crosses interosseous memb. With a. & v.

2. Ant. Tibial a.

- ends at the ankle j. becomes dorsalis pedis a.

Lateral : superficial peroneal n.

Medial : tibial n. Passes deep to the flexor retinaculum

Tibial n. divides into medial & lateral plantar n.,

+ calcaneal n. (sensitive supply of the heel)

Plantar n. : supply intrinsic foot m.(Except for EDB : deep

peroneal n.)

8. Neurovascular structures

Posterior ankle

: sural n. : posterolateral aspect of the inferior third of the

leg, lateral margin of the foot & lateral side of the small toe

: between lateral malleolus & achilles tendon

with small saphenous vein

On the dorsum of the foot: sural n. anastomosis with br. Of

the superficial peroneal n.

Foot

Introduction

Supports body weight, absorbs shock

Congenital, inflammatory, infectious, degenerative causes

Clinical Anatomy

28 bones, 30 joints,100 muscles, tendos, ligaments

Midline : 2nd toe long axis

(Adduction: movement toward 2nd toe, abduction: away from

2nd toe)

Osseous and Articular Anatomy

1. Hindfoot: talus & calcaneus

2. midfoot: navicular, cuboid, 3 cuneiforms

3. forefoot: metatarsals & phalanges

Subtalar joint: talus (large concave facet on the inferior) &

calcaneus (convex posterior articular surface of the superior)

Transverse tarsal joint: talonavicular j~ calcaneocuboid j.

inversion & eversion

Navicular j. : j. with 3 cuneiforms

Tarsometatarsal j. : 3 cuneiforms & cuboid

Forfoot j.

Foot Anatomy

Talus

Calcaneus

navicular

cuneiforms

cuboid

Metatarsals & phalanges

Medial longitudinal Arch

Lateral longitudinal Arch

Plantar aponeurosis

Plantar aponeurosis

Plantar cal-na. L

3 Main arches

1. Medial longitudinal arch

: calcaneus, talus, navicular, 3 cuneiforms, 1~3 metatarsals

concave inferioly

ligaments & muscles

- plantar aponeurosis (calcaneus~ 3 medial prox. Phalanges)

- plantar calcaneonavicular lig. (spring lig.)

(navicular ~calcaneus)

- Flexor hallucis longus m. : bowstring of the arch

- Tibialis posterior & Tibialis anterior : inverting, adducting

3 Main arches

2. Lateral longitudinal arch

: calcaneus, cuboid, 4~5 th metatarsal

(calcaneus~lateral 2 metatarsal heads)

Inferior concavity

Ligaments, muscles & lateral extension of the plantar

aponeurosis

- Peroneus longus: bowstring action

3 Main arches

3. Transverse arch

: base of 5 metatarsals, cuboid, cuneiforms

Ligaments & peroneus longus tendon

At the level of the metatarsal head

- less concave, deep transverse ligament

Soft tissues - dorsal foot

Thin skin: 0.064mm epidermis + subcut. Fat

Dermatomes :

Saphenous n. – medial side

Superficial peroneal n. – central & lateral side

Sural n. – lateral border of the foot

1st web space – deep peroneal n.

Soft tissues – dorsal foot

Extrinsic tendons: TA, EHL, E.D.L

Intrinsic muscles : EDB, EHB

EDB- anterolateral part of the calcaneus ~ EDL tendon

EHB – into prox. Phalanx of the 1st toe

Dorsalis pedis a. : from ant. Tibial a.

Soft tissues - plantar foot

Significant thicker skin

8 times thicker epidermis

Innervation

1. medial plantar n.

2. lateral plantar n.

3. calcaneal branches of tibial & sural n. : sensory br. To heel

Heel pad

: ave. 18mm , multiple fat-containing cells

vertical fibrous & elastic septa shock absorber

Soft tissues - plantar foot

Midfoot level (skin becomes thinner) at the

metatarsophalangeal j.(thicker again for toe off)

Plantar fascia

: fibrous thickening of the superficial fascia: dynamic support

for longitudinal arch

network of compacted collagen fibers

arranged mostly longitudinally

Soft tissues - plantar foot

Plantar Fascia

3 cords of plantar fascia

1. Central: thickest, strongest, triangular

thick posterior and thin anterior, fans out

calcaneus~ flexor tendons of the toes

(into fibrous digital sheath, proximal phalanx)

2. Medial : thin, covers abductor hallucis

3. Lateral : thin, overlies abductor digiti minimi

- maintains medial and lateral longitudinal arch

- firm attachement to skin

Protects underlying skin, n. tendon

Intrinsic muscles & plantar tendons

1 layer

- most superficial : AH, FDB, ADM

AH

: medial calcaneus~ medial base of prox. Phalax of the 1st toe

: large abductor, partially flexor of the 1st toe

(in severe HV, if tendon moves to plantarward, no flexion)

FDB

: from plantar fascia & medial calcaneus~ 4 tendons

flexor of the PIP j.

ADM

:abductor, calcaneus & lateral plantar fascia~5th Prox. phalax

Foot Anatomy Extrinsic T. Intrinsic T.

EDB

EHB

Central-FDB

medial

lateral

Foot Anatomy

1st 2nd 3rd 4th

EHB

FDL

Q-plant ADM

FDB

AH

lumb

FHL

addH

FHB

FDM

P-I

D-I

TP

PL

Anatomy of the Foot- intrinsic

Lateral S Intermed S Medial S

1st Layer

Intrinsic muscles & plantar tendons

2nd layer

1. Quadratus plantae

: medial calcaneus (medial head), lateral calcaneus (lateral

head) ~ FDLtendon (4 tendons)

Assists the action of FDLongus (pulling tendons)

2. 4 Lumbricalis

: from respective tendinous slips of the FDLongus ~ medial

dorsal extensor hood of the 2~5 toes

2nd Layer of Foot

Intrinsic muscles & plantar tendons

3rd layer

1. FHB

: cuboid plantar surface,peroneal groove, lateral

cuneiform(lateral head), plantar surface of the medial &

intermediate cuneiforms, tibialis post. tendon (medial head),

~ proximal phalanx of the 1st toe (medial & lateral)

Flexor of the 1st metatarsophalangeal j.

2. Adductor hallucis

: larger transverse head + smaller oblique head

Adductor of the 1st toe , flexor and maintain transverse arch

3rd Layer of Foot

Intrinsic muscles & plantar tendons

3. FDMb

: plantar surface of the base of 5th metatarsal~ base of 5th

proximal phalanx

Flexor of the 5th toe (MP j)

Intrinsic muscles & plantar tendons

4th layer

Interosseous muscles (4 dorsal & 3 plantar)

1. Dorsal interossei m.

: metatarsal shat~lateral surface of the base of the proximal phalanx of the toes

(except 1st )

Action: Abduct 2nd , 3rd and 4th

Assist lumbricals in extending I-P joints

while flexing metatarso-phalangeal joints

2. plantar interosseous m.

: plantar and medial surface of the base of the 3,4,5 metatarsals~ medial surface

of the base of the prox. Phalanx

Action: Adduct 3rd 4th and 5th toes, Assist lumbricals in extending

interphalangeal joints while flexing metatarso-phalangeal joints

Dorsal Interossei muscles

Plantar Interossei muscle

Intrinsic muscles & plantar tendons

Several tendons : T.P, FHL, F.D.L, PL, PB

T.P – cross medial malleolus to cuneiform

inverter, plantar flexor

FHL – passes under sustentaculum tali, F.D.L~ medial &

lateral sesamoid at the base of the 1st metatarsal , distal 1st toe

flexor of the 1st toe, assists in plantar flexion of the foot

maintenance of medial longitudinal arch

F.D. L – superficial to susten. Tali~ 2 to 5th toe

flexes the phalanges, ankle PF

Intrinsic muscles & plantar tendons

PL, PB - ~ cuboid/ styloid process of the base of the 5th

metatarsal

enters an osteofibrous tunnel, sole of the foot

~ 1st metatarsal & medial cuneiform

evertors, plantar flexors

Plantar Vessels and Nerves

Main arteries

Posterior tibial a.

lateral plantar (large), medial plantar (small) artieries.

pass deep to AbHallucis (with tibial n. br.)

Lateral plantar a: ~ base of the 1st metatarsal bone, joins the

deep plantar br. Of the dorsalis pedis a. plantar a. arch

Joints & para-articular structures of the toes

Metatarsophalangeal, proximal & interphalangeal j.

Synovial- lined j. : flexion, extension

Thick fibrocartilaginous plantar plate

: insert into base of the proximal phalanx

- weight bearing platform, main stabilizer of the

metatarsophalangeal j. resisting dorsiflexion

connected with collateral ligaments

Deep transverse intermetatarsal ligament: connected with

plantar plate

Plantar Plate

PP

Deep tran intermet. L

FDP

PP

Joints & para-articular structures of the toes

1st toe : two phalanges

Two sesamoid bones : medial (tibial) and lateral (fibular) in

plantar aspect of the 1st toe

: embeded in the tendon of the FHB, AH

Capsuloligamentous sling : mechanical benefit during j.

flexion

absorbing weight bearing stress

Hallux sesamoids

Inter-ses L

Thin superfial L

prominence

Bipartite hallux sesamoid

medial

lateral

Usus larger than normal one Cf) same size in fracture